Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Concerns remain about UVB damage to amphibians

02.06.2004


The exposure of amphibians to damaging levels of ultraviolet-B radiation in sunlight is likely a significant part of global amphibian declines, researchers say, despite some recent suggestions to the contrary and a scientific controversy about what role UV-B actually plays in this crisis.



Scientists from the United States, Canada and Spain have outlined their understanding of UV-B’s biological effects on amphibians in an article in Ecology, a professional journal.

In it, they respond to some recent studies that have called into question whether UV-B radiation is causing severe health problems or mortality in amphibians.


"At this point, we believe the broad body of research conclusively demonstrates that UV-B radiation can cause damage to many species of amphibians at every stage of their life cycle, from egg to adult," said Andrew Blaustein, a professor of zoology at Oregon State University and the lead author on the Ecology commentary. "It appears the damage may be even worse than we originally thought a few years ago, and it’s clear that rising levels of UV-B radiation, which could be caused by erosion of Earth’s protective ozone layer, can play at least a part in the amphibian declines we’re seeing around the world."

Most scientists now believe, Blaustein said, that a wide range of causes explain the totality of amphibian declines, and those causes include habitat destruction, disease, parasites, introduced exotic species, environmental contaminants and other aspects of global climate change. In some cases complex chains of interlaced ecological effects can lead to amphibian disease, deformity or death.

But UV-B radiation is still high on the list of concerns, the researchers say.

"At first our field studies showed only the damage that increased levels of UV-B radiation could do to amphibian embryos, where they caused mortality in some species and not in others," Blaustein said. "But with more research we’ve seen how UV-B radiation can affect growth and development in larvae, cause changes in behavior, some deformities, and make the amphibian more vulnerable to disease and death. And in adults, it appears that UV-B radiation can cause retinal damage and blindness."

The evidence gathered from numerous scientists around the world is both alarming and compelling, Blaustein said. Every single amphibian species exposed to natural levels of UV-B radiation has now been found to have some type of health problem, either immediately or later in life.

"Given the numerous other organisms and biological systems that other scientists have already demonstrated to be impacted by UV, it makes sense that some amphibians too would be sensitive to UV radiation," said Lee Kats, a professor of biology at Pepperdine University and another author of the Ecology study.

Some recent studies that have questioned these effects did not have an adequate base of field experiments, made too many assumptions about how UV-B radiation in the life cycle of one species would relate to other species, and fail to understand the natural behavior of amphibians and their evolution, the researchers said in their Ecology article.

"For instance, some researchers have now theorized that amphibians could avoid the effects of UV-B radiation simply by avoiding sunlight or laying their eggs in deeper water," Blaustein said. "But that ignores millions of years of evolution, in which amphibians have developed certain types of behavior for specific reasons. Some species lay their eggs in warm, shallow waters because they are seeking sun and heat, and they need to hatch and grow quickly before the water evaporates or freezes.

"Those types of behavior do not change overnight just because the Earth’s atmosphere may have changed," he said. "It’s not that simple. Moreover, as ponds dry and water levels decrease, amphibians cannot just get out of the sunlight, and they are bombarded by intense UV radiation."

Amphibian declines are an issue that first came to light about 15 years ago and have raised warning flags among many ecologists, who believe they may be a harbinger of ecological changes that are first affecting some of Earth’s most sensitive animals and may later cause more widespread damage to other species.

Aside from amphibian deaths, population declines and localized extinctions, another issue that has raised concern is amphibian deformities. A near epidemic of deformed legs, eye damage and other ailments has been found in more than 60 species of frogs, toads and salamanders in 46 states and across four continents.

At one site near Corvallis, Ore., 75-80 percent of the frogs are deformed, mostly linked to a parasite and other ecological changes. And egg mortality in embryos of the western toad and some other species in parts of the Oregon Cascade Range have approached 100 percent in some recent years.


By David Stauth, 541-737-0787
SOURCES: Andrew Blaustein, 541-737-5356
Lee Kats, 310-506-4310

v | EurekAlert!
Further information:
http://www.orst.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>